Local variable hides global variable¶

ID: cpp/local-variable-hides-global-variable
Kind: problem
Security severity: 
Severity: recommendation
Precision: very-high
Tags:
   - maintainability
   - readability
Query suites:
   - cpp-security-and-quality.qls

Click to see the query in the CodeQL repository

This rule finds declarations of local variables or parameters that hide a global variable. Such declarations create variables with the same name but different scopes. This makes it difficult to know which variable is actually used in an expression.

int i = 10;

void f() {
	for (int i = 0; i < 10; i++) { //the loop counter hides the global variable i
		 ...
	}

	{
		int i = 12; //this variable hides the global variable i
		...
	}
}